Profiling of metal billets



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United States Patent O 3,514,985 PROFILIN G F METAL BILLETS Jacob Marcovitch, Johannesburg, Republic of South Africa, assigner of one-third to Rotary Profile Anstalt, Vaduz, Liechtenstein Filed Aug. 14, 1967, Ser. No. 660,247 Claims priority, application Republic of South Africa, Aug. 22, 1966, 66/5,031 Int. Cl. B21b 13/14 U.S. Cl. 72-241 5 Claims ABSTRACT 0F THE DISCLOSURE The invention provides a method and apparatus for forming metal articles from blanks and billets by rotating a series of work rollers in an orbit, and mounting a blank for its surface zone to be intersected in turn by successive rollers, for the metal to be plastically deformed to the contour of the rollers, without significant disturbance of the metal beyond the surface zone.

This invention relates to the formation of metal articles from billets or blanks by a rolling operation that causes plastic deformation of the billet beyond the elastic limit of the metal, and which is distinct from a cutting operation in that no material, save insignificant flash, is removed from the billet.

Profiling by rolling is a well-known technique. Usually, the blank is rolled between opposed surfaces, often the surfaces of juxtaposed rollers that define a convergent throat through which the billet is drawn or fed. The billet is in continual contact with the surfaces throughout its sojourn in the throat, and receives from the surfaces a contour or contours complementary to that or those of the surfaces.

There is another kind of apparatus in which the blank is acted upon by a series of rollers arranged for movement in an orbit along which they pass one after the other, during the course of which they impinge upon the blank and deform it into intimate contact with a mould or pattern. This involves a plastic flow of metal through the whole mass of the blank and is, in effect, a moulding operation in which the mouldable material is kneaded into the mould by the rollers. Clearly, for any but small components, a considerable input of power is required, and there is the problem that moulds or patterns must be provided.

The object of the present invention is to provide a technique for the formation of metal articles by localised plastic deformation that does not 4require the provision of moulds nor the application of force of the magnitude that is needed to provoke plastic fiow throughout the entire mass of the blank.

According to the invention, the technique consists in rotating a series of small work rollers continuously one after the other in an orbit, mounting a blank for its surface zone to intersect the orbit and thereby to be impinged on in turn by each of the rollers in endless succession, for the metal of the surface zone to be plastically deformed to the contour of the rollers, without significant disturbance of the metal beyond the surface zone.

By surface zone is meant the portion of the blank at and close to the surface, for instance, in a gear wheel the portion of the wheel which contains the gear teeth.

A number of embodiments of apparatus to carry out the method of the invention is shown in the accompanying drawings in which:

FIG. 1 is a fragmentary semi-schematic end view of one form of apparatus, operating on a blank;

3,514,985 Patented June 2, 1970 r ICC FIG. 2 is a similar view of a second form of apparatus;

FIG. 3 is a similar view of a third form of apparatus;

FIG. 4 is a side view of the apparatus of FIG. 3;

FIG. 5 is an end view of a modified form of the apparatus shown in FIGS. 3 and 4;

FIG. `6 is a semi-schematic end view of a single profiling unit operating on a disc to produce a pinion;

FIG. 7 is a fragmentray detail view of the action of a Work roller on a disc upon which gear teeth are being formed;

FIGS. 8 and 9` are semi-schematic views illustrating the intersection of the paths of a series of Work rollers with the circumference of a disc on which gear teeth are formed;

FIG. 10 is a fragmentary view illustrating the action of a backed series of work rollers on a stack of metal strips to produce hacksaw blades; 4

FIG. l1 is a fragmentary view illustrating the action of a work roller on a blank in the form of a bar to produce rack teeth;

FIG. l2 is a cross-sectional view through a cylindrical blank, surrounded partially by working rollers;

FIG. 13 is a side view of the arrangement of FIG. l2, illustrating one profiling unit in operation.

In the drawings generally, the apparatus to carry out the method of the invention consists basically of a unit in the form of a cage 10 in which are journalled a series of small Work rollers 12, each individually rotatable. The rollers are usually identical. The cage is usually composed of two annular walls (FIG. 4) that are co-axial and are formed with registering apertures to receive pintles 14 projecting from the rollers to either side.

The series of rollers is arranged for rotation in a fixed orbit, which may be circular, if the cage is circular and arranged to rotate about its axis (FIG. l). However, the cage may be oblong and articulated in the manner of a caterpillar tread, as in FIG. 2, where the orbit is elliptical. It is essential that the work rollers be backed. In FIGS. l, 3 and 4, the backing is a central roller 16 against which stub axles of each roller bear, and which is held in place by structure not illustrated. Additionally, the unit may be backed by a roller or rollers 18 (FIG. l) which may themselves be backed by other rollers, and so on.

In FIG. 2, the backing is provided by a stationary member 20 around which the articulated cage 10 and the rollers 12 orbit. The back-up member 20 is held in a framework or similar structure, not illustrated.

In FIG. 2 (and indeed in FIG. l if it be desired) the work rollers may be backed by a series of small rollers 22 carried by the cage 10 (or by another cage). The rollers 22 are themselves backed by the backing member or roller 20- or 18. (In FIGURE 5, a concave backing member 13 is shown.)

Where a single row of rollers is used in the unit in conjunction with a circular back-up member, as in FIGS. l, 3, 4, 5 and 6, the cage is allowed to idle and the backup roller is driven to impose orbital motion on the work rollers. Where two rows of rollers are used, as in FIG. 2, the back-up member is kept stationary and the cage is driven. The drive mechanism may be of any suitable kind, such as gearing or, in the case of a chain cage, sprocket wheels.

The basic units of the invention may be operative singly, as is seen in FIGS. 3, 4 and 5, in which case they are associated with structure such as rollers 24 which back the blank 26; or in conjunction with another unit or units, as seen in FIG. l. Whichever arrangement is employed, the unit defines with the other unit or units, or with the rollers '24, a profiling space Within which a blank 26 is accommodated. External support such as chucks (not illustrated) may be provided to support the blank axially, or toprovide any desired feed and/ or rotation of the blank relatively to the units.

The geometry of the apparatus is such that the orbiting rollers 12 impinge against the surface of the blank 26 with the aim of causing plastic flow of the metal composing the surface zone but without disturbance of profounder zones. This can be achieved in the cold, but it is preferred that the blank be heated superficially to assist localised plastic flow. To this end, an induction heating system such as shown at 29, FIG. 4, may be provided to heat elements of the blank about to be hammered by the work rollers 12.

The apparatus of FIGS. l, 3, 4, and 5 operate upon a cylindrical or cylindroidal blank that is rotated with its axis substantially parallel to the axes of the work rollers, to impose on it a profile which is continuous around the circumference, such as annular or (as seen in FIG. 4) helical grooves. However, it is not essential that this be so. Depending upon the operation to be performed on the blank, any suitable relative movement between it and the profiling unit can be employed. Furthermore, the blank need not be a solid of revolution.

In FIG. 6, the unit 10, 12 is arranged for rotation about its axis, as in some of the previous embodiments, but the blank is a disc 30 set on a shaft 31, 4which is clamped by means not illustrated, and arranged for rotational movement about its axis. As the unit 10, 12 rotates, as shown by the arrows, the rollers 12 in turn impinge on the surface of the blank 30 to profile it, parallel to the axis o-f the shaft so that the profile is imposed on it along the length of the blank. It will usually be the case that the blank 30 is not rotated at this stage, so that the profile will be straight along its length, but it is conceivable that some rotation will take place so that the profile -will be helical.

To form a pinion With straight spur teeth, the blank 30 is turned through the required degree after each pass beyond the unit 10, 12 to extend the area of profiling, and so on.

Of course, the blank shown in this and the other gures need not be solid, and could equally be hollow, for instance a tube. A rotating tube, with its axis square or nearly square, to the path of the work rollers could also yield circumferential or helical fins.

In FIG. 7, the blank is a disc 34, and the rollers 12, of which only one is shown, are formed with circumferential ribs 36. A backing roller 25 is complementally ribbed to support the roller 12. The disc 34 is mounted for rotation about its axis and its shaft is sturdily supported. The circumferential ribs 36 profile the disc to form teeth 40 and the disc is slowly rotated until the whole periphery has been toothed. Since the disc is rotating continuously, the orbit of the rollers must be skewed, that is, inclined at an angle to the axis of the disc, so that the ribs on each roller register with the indentations made in the disc by its predecessor or predecessors. Careful control must of course be exercised over the relative speeds and degree of skewing of the unit and the blank.

Two examples of this situation are shown in FIGS. 8 and 9, each illustrating the orbital path of sets of rollers 12 in relation to the circumference of the blank 34 (shown fragmentarily in developed aspect). In FIG. 8, two rollers are shown, their paths so intersecting that of the circumference of the blank that each circumferential rib 36 registers in an indentation made by the rib of the preceding roller. The leading rib on each roller, of course, impresses an indentation in an unmarked zone of the disc. In FIG. 9, a similar arrangement is illustrated, except that the ribs of the rollers 12 are staggered with respect to each other. Here, the three rollers 12 that are shown leftmost in the drawing register in the same indentations without initiating the formation of a new tooth. The roller 12 on the extreme right, however, does begin the deformation of a new tooth. In both cases, a straight gear tooth on the blank produced, each tooth being formed by localised plastic fiow of the metal under the action of several rollers.

In FIG. l0, the blank 40 is a pack of thin metal strips which is mounted for movement at right angles to the plane in which the workrollers 44 orbit. The work rollers are formed with circumferential saw-toothed ribs 45 Which impose saw-tooth indentations into one side of the blank 40 as it is drawn past the rollers. The blank is,i of course, suitably backed by fixed structure 41. VThe resulting components are blades for a hacksaw .or a lbandsaw and are suitably set and hardened. The arrangement shown in FIG. ll is, in fact, that of FIG. 2, the rollers 44 being the rollers 12, and the hacking rollers 46 the rollers 22. The chain' 10 is shown, and the work rollers and backing rollers are mountedVV on it by pintles 48, 50 projecting from the rollers. I l

InFIG. ll, illustrating the production of a gear rack from a square-sectioned blank 43, the work rollers 47 are backed by a roller 52 suitably profiled to mate with the ribs 42 on the work rollers. Again, there is suitable co-ordination between spacing and feed rates of the profiling unit and the blank.

In FIGS. l2 and 13, a series of units 10, 12 is mounted around a cylindrical blank 52 which is moved axially and simultaneously profiled by the rollers of the units. The units may extend around the full periphery of the blank, so that the whole of it is profiled in one pass.

Almost any profile can be applied to blanks by the technique of the invention and many components, hitherto made laboriously by machining, casting, forging or moulding, can be made at considerable saving of time and material. Indeed, components which are at present producible only at very large expense and with doubtful efiiciency can be readily produced. An example which may be cited is that of raising ribs on members for air-frames.

I claim:

1. Apparatus for proling the surface of a metal blank by rolling, comprising (a) a series of small work rollers each having a proled central portion and circular section ends of lesser diameter than the central portion, (b) an endless cage in which the work rollers are mounted at spaced intervals, each work roller being individually rotatable in the cage; and (c) backing means around which the cage and work rollers move in an endless path so that the work rollers impinge in succession on the blank and their central portions roll on the surface of the blank to cause it to assume their profile, the work rollers rolling in line contact on the backing means, the total length of said line contact being greater than the length of the central portion of each work roller. f

2. Apparatus as claimed in claim 1, in which the ends of the work rollers roll on the backing means in linecontact therewith and the combined length of the ends of each work roller is greater than the length of its central portion.

3. Apparatus as claimed in claim 1, in which the backing means is recessed behind the central portions of the rollers complementally to the profile of said central portion, the central portions rolling in line contacton the recessed backing means.

4. Apparatus as claimed in claim 1, in which the backing means is a massive circular body in which meansis provided to drive the backing tbody about its axis to cause the work rollers to move in their path, and in which the work rollers roll in line contact directly on the surface of the backing body.

5. Apparatus as claimed in claim 1, in which the backing means comprises a massive non-circular body and a series of backing rollers which are recessedfbetween their ends to accommodate the central portion of the work roller and which are mounted in the cagewhich is flexible for movement in the path with the cage and the -work rollers, each work roller being supported on two backing rollers with its central portion received in the recesses in References Cited UNITED STATES PATENTS 8/1880 Prosser 72--100 8/1905 Pogany et al. 72-100 6 1,929,987 10/1933 Mead 72-190 2,565,780 8/1951 Offutt 72-190 3,348,401 10/1967 `Sporck 72-194 5 LOWELL A. LARSON, Primary Examiner U.S. Cl. X.R. 72-100, 126

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent NO 3,514 ,985 June 2 1970 Jacob Marcovitch It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, line 4, cancel of one-third".

Signed and sealed this 2nd day of March 1971.

(SEAL) Attest: Edward M. Fletch, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR. 

